Readily available and affordable consumer-grade electronics, with ever-increasing sensing, computing, and communication capabilities, have provided the ground for distributed computation and data collection systems. Crowd-sensing applications rely on volunteers providing access to their personal devices-a category encompassing smartphones, wearables, vehicles, and a wide range of `Internet of Things' appliances-and using them as sensors. These systems rely on the willingness of participants to invest in a common cause, which often entails explicit efforts from users, occupation of hardware resources, and risks of sharing private data. Incentives and rewarding schemes are adopted to encourage user participation. This paper introduces the "Worth One Minute" (WOM) platform: an implementation of a general-purpose rewarding system based on anonymous vouchers. The platform is designed to reward user efforts towards the common good, rewarding their contributions and the intrinsic social value they provide, while preserving their anonymity.